1. Field of the Invention
The present invention relates to a liquid ejecting method, a liquid ejecting device, and a liquid ejecting system for foaming and ejecting a liquid by heat generated by an electro-thermal conversion element.
2. Description of the Related Art
Representative ejecting methods in a liquid ejecting head mounted on a liquid ejecting device include a liquid ejecting head using an electro-thermal conversion element. This liquid ejecting head has the electro-thermal conversion element provided in a liquid chamber and applies thermal energy to the liquid by supplying an electric pulse which is a print signal to the electro-thermal conversion element for heat generation. Then, by using an air-bubble pressure at the time of foaming (boiling) of the liquid generated by a phase change of the liquid in a case that the thermal energy is applied, a liquid (hereinafter also referred to as ink) is ejected to a sheet from a micro ejecting port. In this liquid ejecting head using the electro-thermal conversion element, at the time of defoaming of the air bubbles generated by heating the ink with the electro-thermal conversion element, the liquid rapidly flows in at a disappearance point, and cavitation occurs. This cavitation generates an impact force on the electro-thermal conversion element.
FIG. 9 is a schematic diagram of a vicinity of an ejecting port of a prior-art liquid ejecting head seen from a front. In a configuration in which a center line of an ink channel 5 for supplying ink to the ejecting port matches a center line of an electro-thermal conversion element 1, a flow of the ink from a common liquid chamber 8 toward a pressure chamber 7 through the ink channel 5 is generated symmetrically with respect to the center line of the electro-thermal conversion element 1. Thus, the air bubbles generated by heating the ink with the electro-thermal conversion element 1 are stably defoamed symmetrically with respect to the center line on the electro-thermal conversion element 1. In the configuration in which a defoaming position is stable as above, a specific spot in the electro-thermal conversion element receives the impact force caused by the cavitation, and thus, there is a problem that the electro-thermal conversion element 1 is easily damaged, and a durability life becomes short.
On the contrary, Japanese Patent Laid-Open No. 2002-321369 proposes a configuration in which the pressure chamber has a columnar shape, the center line of the ink channel is offset to the center of the electro-thermal conversion element and moreover, the center of the ejection port is offset from the center of the electro-thermal conversion element to the common liquid chamber side. With this configuration, the ink flow from the common liquid chamber through the ink channel toward the pressure chamber washes away the air bubbles to a position biased to a side of the electro-thermal conversion element. Then, at this biased position, final defoaming can be made to occur in a relatively wide region extending vertically in the vicinity of a side edge of the pressure chamber, whereby cavitation generation regions are distributed, and an influence of the cavitation can be reduced.
However, with a recent trend to an ejecting port with higher density in order to obtain high definition print, it is difficult to constitute the pressure chamber having a columnar shape. Moreover, in order to handle improvement of a print speed and ink with viscosity higher than before, the ink channel needs to be widened, and a method of controlling the ink flow by the configuration of the ejecting port and of distributing the cavitation generation regions has become difficult.